Electrical breast pump and system

ABSTRACT

An electrical breast pump may include a permanently unobstructed continuous passageway across the diaphragm and a rolling diaphragm that is movable between a vent orientation and a vacuum orientation, or a vent piston configured to actuate a closure between a vent orientation and a vacuum orientation so that a pressure chamber is selectively in direct communication with atmospheric pressure.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application that claims priority toand the benefit of co-pending U.S. patent application Ser. No.14/725,739, filed on May 29, 2015, the disclosure of which is fullyincorporated herein by reference.

FIELD OF THE DISCLOSURE

The present disclosure generally relates to electrical breast pumps andelectrical breast pump systems. More particularly, the presentdisclosure relates to a simple electrical breast pump and electricalbreast pump system for extracting milk from a human breast that quicklyattains a desired setting.

BACKGROUND

Most prior art breast pumps designed for extracting milk are concernedonly with controlling the rate at which a negative pressure is appliedto the breast and, in some cases, the amount of negative or vacuumpressure. However, the amount of milk volume obtained in response to aconstant average suction is quite low compared to that obtained by asuckling infant.

Recently, breast pump systems have been introduced that use a constantlyrunning positive displacement vacuum pump, sense and monitor thenegative pressure or vacuum and open a valve in response to the sensedvacuum in excess of the vacuum limit in order to decrease the vacuum toa desired point. Such systems are complex, which reduces reliability,and costly, which discourages breast feeding.

Other conventional breast pump systems, see FIGS. 3 and 4, include apump assembly 10 having a reciprocating piston assembly 20 driven by areversible motor 14.

A rolling diaphragm 22 is connected via circumferential tension at aninner end 24 to a center post 26 of the piston assembly 20 and at anouter end 28 captured between the piston housing 30 and the drivehousing 32. The vent piston 34 includes, in FIG. 3, a vent 36 formed asa bore that extends from a distal end 38 (at the top wall 37) to aproximal end 40 disposed adjacent the lower end of a side wall 42 of thevent piston 34, and in FIG. 4, a vent 36 formed as a bore that extendsthrough a side wall 42 of the vent piston 34 to a channel 44 formedaround the center post 26. Both the vents 36 enable the pressure chamber46 to communicate with a portion 48 of the diaphragm 22 adjacent toconnection to the center post 26.

In theory, it was thought and desired that the portion 48 would overcomethe circumferential tension when a slight positive pressure wasgenerated in the pressure chamber 46 when the vent piston 34 wasdisposed adjacent a port formed in an end wall of the piston housing 30(e.g., near maximum extension) and move or deflect in the direction ofthe threaded piston 50 to facilitate defining an intermittent passage toatmosphere every time the vent piston 34 reached near maximum extensionfrom the drive screw 52. However, it was discovered through testing andoperation that the portion 48 was not consistently moving or deflectingas desired and that the portion 48 was not moving at maximum extensionof the piston assembly 20 in response to the slight positive pressurepresent in the pressure chamber 46 and/or the portion 48 was moving nearthe beginning of a vacuum retraction pull by the piston assembly 20 (inan opposite direction from what was desired) so that the desired vacuumis not achieved. In other words, the breast pump system was too closedor only somewhat intermittently openable to atmosphere resulting inpainful constant increasing vacuum profiles or under vacuum profilesthat take a considerable time to operate properly, raising distrust asto proper operation. As a result, the conventional breast pump systemtook on average at least 20-30 seconds to reach a consistent steadystate pressure or vacuum recovery profile. Sometimes it would takelonger and still further sometimes it would never reach the desiredconsistent steady state vacuum recovery profile.

FIG. 5 is a graph of pressure versus time, illustrating the conventionalprior art breast pump system (as conceptually shown in FIG. 1 andincluding as pump assembly as shown in either FIG. 3 or FIG. 4) vacuumrecovery profile. One will note that in concept nearly any breast pumpsystem includes, as shown in FIG. 1, a pump assembly housing 54 (withthe pump assembly 10 disposed within, but not shown in this FIG. 1), apair of collection units 56 each connected via tubing to a single portof the pump assembly and including breast flanges 58. As shown in FIG.5, neither of the flanges 58 experiences a quick vacuum recovery profilefrom a 0 mm Hg reading (i.e., atmospheric pressure), where the desiredvacuum profile smoothly oscillates between 0 mm Hg and 200 mm Hg (forthis testing purpose only, in practice the maximum vacuum is selectableby the user). Rather, one flange 58 experiences a weak but steadilyincreasing vacuum profile (i.e., the lower trace 60) and the otherflange 58 experiences a weak, barely increasing vacuum profile (i.e.,the upper trace 62). Usually, the lower trace 60 may stabilize at thedesired or called for 200 mm Hg and the upper trace 62 will eventuallymatch the vacuum recovery profile of the lower trace 60. However, asignificant disadvantage is the discomfort of the nursing mother thatdiscourages her from breast feeding with the unnecessary complications.Further, it has been commonly observed that the lower trace 60 and/orboth traces 60, 62 may actually continue to increase the amount ofvacuum until reaching a painful level (e.g., approximately 250-270 mmHg) where the nursing mother must rest operation of the prior art deviceby deactivating the pump assembly and removing the flange. Thereafter,the entire process must start over, which most likely is a repeat of thevacuum recovery profile as shown in FIG. 5. Another situation where aquick vacuum recovery profile is desired is when there is anintermittent leak in the system. Obvious disadvantages are not only thediscomfort and possible pain, but also the time delays and frustrationand distrust with faulty operation.

Therefore, there is a need in the art for simple, reliable electricalbreast pump and electrical breast pump system that quickly attains andmaintains a desired setting regardless if starting anew, after a breakor as a result of a system leak and that overcomes the disadvantages ofthe complex and unreliable prior art systems.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure will be more readily understood in view of the followingdescription when accompanied by the below figures and wherein likereference numerals represent the elements, wherein:

FIG. 1 illustrates a perspective view of one embodiment of an electricalbreast pump system the present disclosure.

FIG. 2 illustrates an exploded view of one embodiment of a pump assemblyof the present disclosure.

FIG. 3 illustrates a cross-section view of one embodiment of a pumpassembly of a prior art electrical breast pump.

FIG. 4 illustrates a cross-section view of another embodiment of a pumpassembly of a prior art electrical breast pump.

FIG. 5 is a graph of pressure versus time, illustrating a prior artbreast pump system vacuum recovery profile.

FIG. 6 illustrates a cross-section view of the pump assembly of FIG. 2disposed in a vent orientation.

FIG. 7 illustrates a cross-section view of the pump assembly of FIG. 2disposed in a vacuum orientation.

FIG. 8 is a graph of pressure versus time, illustrating a breast pumpsystem vacuum recovery profile for one embodiment of the pump assemblyof the present disclosure.

FIG. 9 is a graph of a pressure versus time, illustrating a breast pumpsystem vacuum recovery profile for one embodiment of the pump assemblyof the present disclosure with an annotated piston assembly cycle.

FIGS. 10A and 10B illustrate respective cross-section and bottom viewsof another embodiment of a diaphragm for a piston assembly of thepresent disclosure.

FIGS. 11A through 11I illustrate cross-section views of otherembodiments of the piston assembly of the present disclosure.

FIG. 12 illustrates a cross-section view of another embodiment of pistonassembly of the present disclosure including a drive screw having abore.

FIGS. 13A and 13B illustrate cross-section views of embodiments of adynamic vent for the pump assembly of the present disclosure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following disclosure as a whole may be best understood by referenceto the provided detailed description when read in conjunction with theaccompanying drawings, drawing description, abstract, background, fieldof the disclosure, and associated headings. Identical reference numeralswhen found on different figures identify the same elements or afunctionally equivalent element. The elements listed in the abstract arenot referenced but nevertheless refer by association to the elements ofthe detailed description and associated disclosure.

Generally, an electrical breast pump as disclosed herein may include apermanently unobstructed continuous passageway that is disposed atatmospheric pressure and defined across a rolling diaphragm that ismovable between a vent orientation and a vacuum orientation, or a ventpiston configured to actuate a closure between a vent orientation and avacuum orientation so that a pressure chamber is selectively in directcommunication with atmospheric pressure.

In one aspect of the present disclosure, an electrical breast pump mayinclude a housing assembly having a piston housing and a drive housinghaving an opening in direct communication with atmospheric pressure. Apiston assembly may include a vent piston and a drive piston. The ventpiston has a top wall, a channel defined by the top wall, a side walland a center post, and a vent defined to extend through the side wall incommunication with the channel. The drive piston having a top wall witha vent passage defined therethrough. A rolling diaphragm may include anouter end, an outer margin disposed adjacent the outer end. The outerend and outer margin are sealingly captured between the piston housingand the drive housing. An inner end and an inner margin disposedadjacent the inner end are sealingly captured between the vent pistonand the drive piston to cooperatively define a pressure chamber betweenthe diaphragm, piston housing and vent piston. A permanentlyunobstructed continuous passageway across the diaphragm that is disposedat atmospheric pressure is defined by the vent, the channel, the innerend that is spaced from the center post, the vent passage and theopening. The diaphragm is movable between a vacuum orientation and avent orientation in response to cyclic movement of the piston assembly.The vacuum orientation is defined when an outer opening of the vent issealed by the diaphragm, and the vent orientation is defined when theouter opening of the vent is uncovered by the diaphragm so that thepressure chamber is in direct communication with atmospheric pressurevia the permanently unobstructed continuous passageway across thediaphragm.

In other aspects of the present disclosure, the portion is the entiretyof the inner end or is defined by the inner end having a crenelatedcontour. In another aspect, a plurality of ribs may extend from thecenter post to engage the inner end, or the center post may have arecess formed over a section adjacent the inner end. In yet anotheraspect, the vent piston may include a projection extending from the sidewall into contact with the drive piston such that the portion engagesthe projection, or such that the inner edge engages the projection. Instill another aspect, the drive piston may include an extension thatprojects from the top wall into contact with the vent piston such thatthe portion engages the extension, or such that the inner edge engagesthe extension. In a further aspect, an insert is disposed between thedrive piston and the vent piston such that the portion engages theinsert, or such that the inner edge engages the insert.

In a still further aspect of the present disclosure, a breast pumpassembly may include a housing assembly including a piston housing and adrive housing having an opening in direct communication with atmosphericpressure. A piston assembly may include a vent piston and a drivepiston. The vent piston may have a top wall and a channel defined by thetop wall, a side wall, a hollow center post, a vent defined to extendthrough the side wall in communication with the channel, and a secondvent defined to extend through a wall of the center post into thehollow. The drive piston may have a hollow center post with a ventpassage defined therethrough so that the hollow center posts of the ventpiston and the drive piston are longitudinally aligned in registrationand sealingly connected. A rolling diaphragm may include an outer end,and an outer margin disposed adjacent the outer end that are sealinglycaptured between the piston housing and the drive housing. The diaphragmmay also include an inner end circumferentially engages the center post,and an inner margin disposed adjacent the inner end is sealinglycaptured between the vent piston and the drive piston to cooperativelydefine a pressure chamber between the diaphragm, piston housing and ventpiston. A permanently unobstructed continuous passageway across thediaphragm that is disposed at atmospheric pressure may be defined by thevent, the channel, the second vent, the hollow of the center post of thevent piston, the hollow of the center post of the drive piston, the ventpassage and the opening. The diaphragm is movable between a vacuumorientation and a vent orientation in response to cyclic movement of thepiston assembly, such that the vacuum orientation is defined when anouter opening of the vent is sealed by the diaphragm, and the ventorientation is defined when the outer opening of the vent is uncoveredby the diaphragm so that the pressure chamber is in direct communicationwith atmospheric pressure via the permanently unobstructed continuouspassageway across the diaphragm.

In another still further aspect of the present disclosure, a breast pumpassembly may include a housing assembly having a piston housing having avent passage in direct communication with atmospheric pressure and aclosure movably connected to the piston housing that is configured toselectively seal the vent passage, and a drive housing. A pistonassembly may include a vent piston configured to actuate the closurebetween a vent orientation and a vacuum orientation, and a drive piston.A rolling diaphragm may include an outer end, and an outer margindisposed adjacent the outer end that are sealingly captured between thepiston housing and the drive housing. The diaphragm may also include aninner end and an inner margin that is sealingly captured between thevent piston and the drive piston to cooperatively define a pressurechamber between the diaphragm, piston housing and vent piston. The ventorientation is defined when the vent piston actuates the closure to openthe vent passage so that the pressure chamber is in direct communicationwith atmospheric pressure and the vacuum orientation is defined when thevent piston is disengaged from the closure.

In another aspect of the present disclosure, the diaphragm may bedisposed in the vent orientation between approximately 0.1 seconds and1.2 seconds of each cycle of the piston assembly, depending on the speedsetting or the extent of the longitudinal displacement of the pistonassembly. In yet another aspect, the diaphragm may be disposed in thevent orientation between approximately 15% to 60% of each cycle of thepiston assembly, depending on the speed setting or the extent of thelongitudinal displacement of the piston assembly. In a preferredembodiment, the diaphragm is disposed in the vent orientation between0.2 seconds and 1.0 second, or between approximately 20% and 50% of eachcycle of the piston assembly, depending on the speed setting or theextent of the longitudinal displacement of the piston assembly.

FIGS. 2 and 6-13 show various different embodiments of an electricalbreast pump assembly 100 that may include a permanently unobstructedcontinuous passageway that is disposed at atmospheric pressure anddefined across a rolling diaphragm 122 that is movable between a ventorientation (FIG. 6) and a vacuum orientation (FIG. 7), or a vent piston134 configured to actuate a closure between a vent orientation and avacuum orientation so that a pressure chamber 146 is selectively indirect communication with atmospheric pressure 102.

FIG. 2 illustrates an exploded view of one embodiment of a pump assembly100 of the present disclosure. A housing assembly 129 may include apiston housing 130 and a drive housing 132. The piston housing 130 mayinclude a flange 231 and a sidewall 233 have an exterior surface contourthat is different from an interior surface contour. The exterior surfacecontour has a substantially linear taper from the flange to an end wall235. The interior surface contour has a first component that is spacedfrom a piston assembly 120 sufficiently to allow a rolling diaphragm 122to complete a one hundred eighty degree bend and accumulate in suchspace and a second component that is disposed in close proximity to avent piston 134 to facilitate alignment and constrained movementthereof. Both of the first and second components have a slight taper ordraft to facilitate removal from the mold, being preferable formed fromplastic, synthetic, polymer, composite, etc. or the like types ofmaterials. A single port 236 is preferable defined in the end wall 235.However, it is within the teachings of the present disclosure thatmultiple ports may be defined in the end wall 235. The drive housing 132may include a flange 237 and a sidewall 238 having an opening 239 indirect communication with atmospheric pressure 102. The flanges 231 and237 preferably cooperatively engage to sealingly capture an outer end128 of the diaphragm 122 therebetween.

A piston assembly 120 in one embodiment may include at least a ventpiston 134 and a drive piston 150 securely connected together such as bymechanical fastener, adhesive, welding, other connection techniques,etc. or the like. The vent piston 134 may have a top wall 137 and achannel 144 defined by the top wall 137, a side wall 142 and a centerpost 126, such that the channel 144 is configured generally as anannular channel about the center post 126. Preferably, a vent 136 isdefined as a bore or passageway that extends through the side wall 142so that it is in direct communication with the channel 144. The drivepiston 150 may have a top wall 251 with a vent passage 252 definedtherethrough and a center post 253 having a proximal end (i.e., oppositethe top wall 251) with an interior surface configured complementarily toengage a drive screw 152 such that rotation of the drive screw 152 bythe reversible motor 140 selectively cyclically moves the pistonassembly 120 in an oscillating movement from a start position where thevent piston 134 is disposed adjacent the end wall 235 to an adjustablyselectable end position where the vent piston 134 is disposed at adesired extent from the end wall 235 in order to generate a pre-selectedamount of vacuum pressure and then back to the start position to definea single cycle or piston stroke for which there is a correspondingvacuum profile curve. The piston assembly 120 is preferably formed fromplastic, synthetic, polymer, composite, etc. or the like types ofmaterials.

A rolling diaphragm 122 may include an outer end 128, an outer margin223 disposed adjacent the outer end 128. It is within the teachings ofthe present disclosure that the outer margin 223 is configured as anarea generally bounded by the outer end 128 and extending annularlytoward an inner end 224 a sufficient distance in order to facilitate thedesired functionality as described herein. One of skill in the art mayrecognize such configuration as generally rim- or ring-shaped. In onepreferred embodiment, both of the outer end 128 and outer margin 223 aresealingly captured between the piston housing 130 and the drive housing132. The diaphragm 122 may also include an inner end 224 and an innermargin 225 disposed adjacent the inner end 224. It is within theteachings of the present disclosure that the inner margin 225 isconfigured as an area generally bounded by the inner end 224 andextending annularly toward the outer end 128 a sufficient distance inorder to facilitate the desired functionality as described herein. Oneof skill in the art may recognize such configuration as generally rim-or ring-shaped. In one embodiment, the inner margin 225 is sealinglycaptured between the vent piston 134 and the drive piston 150 to securethe diaphragm 122 in position and to cooperatively define a pressurechamber 146 as a volume between the diaphragm 122, piston housing 130and vent piston 134. The diaphragm 122 is preferably formed fromsynthetic, polymer, rubber, latex, composite, etc. or the like types ofmaterials.

A permanently unobstructed continuous passageway 300 across thediaphragm 122 that is disposed at atmospheric pressure (since it is opento atmospheric pressure 102 at one end) is defined by the vent 136 whichis in direct communication with the channel 144 which is in directcommunication with a portion 226 of the inner end 224 that is spacedfrom the center post 126 which is in direct communication with the ventpassage 252 which is in direct communication with the opening 239.

The diaphragm 122 is movable between a vacuum orientation (see FIG. 7which illustrates a cross-section view of the pump assembly of FIG. 2disposed in a vacuum orientation) and a vent orientation (see FIG. 6which illustrates a cross-section view of the pump assembly of FIG. 2disposed in a vent orientation) in response to cyclic reciprocatingmovement of the piston assembly 120 by completing, on each cycle, a onehundred eighty degree bend and accumulating (by rolling the diaphragm122) in the space defined by the first component of the inner surface ofthe piston housing 130, such that the vacuum orientation is defined whenan outer opening 236 of the vent 136 is sealed (i.e., covered by orcontiguous with the diaphragm so as to isolate the pressure chamber 146on one side of the diaphragm from the permanently unobstructedcontinuous passageway 300 that extends across the diaphragm 122) by therolled diaphragm 122 (see FIG. 7), and the vent orientation is definedwhen the outer opening 236 of the vent 136 is uncovered by thesubstantially unrolled diaphragm 122 so that the pressure chamber 146 isin direct communication with atmospheric pressure 102 via thepermanently unobstructed continuous passageway 300 across the diaphragm122. It will be recognized by one of skill in the art that when thepressure chamber 146 is at atmospheric pressure 102, the remainder ofthe breast pump system will also be disposed at atmospheric pressure(i.e., tubing, collection units 56, breast flanges 58, etc.), whichcreates a pleasing sensation to the user, which is akin to a sucklinginfant.

FIG. 8 is a graph of pressure versus time, illustrating a breast pumpsystem vacuum recovery profile for one embodiment of the pump assembly100 of the present disclosure. The two vacuum profile traces (i.e., forflange 58 vacuum left and flange 58 vacuum right) are nearlyindistinguishable. One of skill in the art will recognize that thissystem is operating equivalently on both sides. Additionally, themaximum intended or desired vacuum (i.e., −200 mm Hg) for this testexample only is reached immediately (i.e., in less than two completecycles and less than 2 seconds). Furthermore, the maximum intended ordesired vacuum is maintained at the constant level and the entire systemis reset to atmospheric pressure on every cycle.

FIG. 9 is a graph of a pressure versus time, illustrating a breast pumpsystem vacuum recovery profile for one embodiment of the pump assembly100 of the present disclosure with an annotated piston assembly cycle.The first phase of the piston assembly 120 cycle is where the breastpump system is open to atmospheric pressure 102 across the diaphragm. Inthis disclosure, it is referred to as the vent orientation (see FIG. 6)where the vent orientation is defined when the outer opening 336 of thevent 136 is uncovered by the substantially unrolled diaphragm 122 sothat the pressure chamber 146 is in direct communication withatmospheric pressure 102 via the permanently unobstructed continuouspassageway 300 across the diaphragm 122. In one preferred embodiment,the diaphragm may be disposed in the vent orientation (FIG. 6) betweenapproximately 0.1 seconds and 1.2 seconds of each cycle of the pistonassembly, depending on the speed setting or the extent of thelongitudinal displacement of the piston assembly. In yet another aspect,the diaphragm may be disposed in the vent orientation (FIG. 6) betweenapproximately 15% to 60% of each cycle of the piston assembly, dependingon the speed setting or the extent of the longitudinal displacement ofthe piston assembly. In a preferred embodiment, the diaphragm isdisposed in the vent orientation (FIG. 6) between 0.2 seconds and 1.0second, or between approximately 20% and 50% of each cycle of the pistonassembly, depending on the speed setting or the extent of thelongitudinal displacement of the piston assembly.

The second phase of the piston assembly 120 cycle is where the breastpump system builds a vacuum pressure in the pressure chamber 146 duringa vacuum stroke. After the outer opening 236 of the vent 136 is sealedor covered by the overlapping diaphragm 122 when rolled, the pressurechamber 146 is no longer open to atmospheric pressure 102 and subsequentretraction of the piston assembly 120 from the end wall 235 createsvacuum pressure in the breast pump system since it is closed at theother end (i.e., breast flanges 58 against the breasts of the user) andthe volume is increased. The distance that the piston assembly 120 ismoved away from the end wall 235 correlates to the desired amount ofvacuum that is desired to be generated in the system by the user. Thisdesired amount is adjustable to the needs of the user.

The third phase of the piston assembly 120 cycle is where the breastpump system reduces the vacuum in the pressure chamber 146 during areturn stroke. The piston assembly 120 is moved toward the end wall 235to reduce the volume of the closed breast pump system and therebyincrease the pressure or decrease the vacuum pressure present in thebreast pump system to the same level as where the vacuum stroke started.

Then, the first phase starts again when the diaphragm is return to thevent orientation and the breast pump system is open to atmosphericpressure.

FIGS. 10A and 10B illustrate respective cross-section and bottom viewsof another embodiment of a diaphragm 122 for a piston assembly of thepresent disclosure. In this embodiment, the inner end 224 and the innermargin 225 of the diaphragm 122 have been configured such that the innerend 224 engages the center post 126 of the vent piston 134 and theportion 226 is configured as openings formed in the inner margin 225, soas to maintain the permanently unobstructed continuous passageway 300across the diaphragm 122 for the advantages described herein. Otherwise,the remainder of the structure and functionality of the pump assembly100 remains as described herein, when used in connection with thisembodiment of the diaphragm 122. In particular, the inner edge 224 andportion 226 can be described as having a crenelated configuration andone of skill in the art will recognize that other similar configurationsthat provide the same functionality are within the scope of the presentdisclosure.

FIGS. 11A through 11I illustrate cross-section views of otherembodiments of the piston assembly 120 of the present disclosure. FIGS.11A and 11B illustrate respective bottom and cross-section views ofanother configuration of the piston assembly 120 where the center post126 of the vent piston 134 includes a plurality of ribs 324 that extendradially therefrom into the channel 144 such that the inner end 224 ofthe diaphragm 122 circumferentially engage the ribs 324 and the portions226 are disposed across the gap defined by adjacent ribs 324, so as tomaintain the permanently unobstructed continuous passageway 300 acrossthe diaphragm 122 for the advantages described herein. Otherwise, theremainder of the structure and functionality of the pump assembly 100remains as described herein, when used in connection with thisembodiment of the piston assembly 120.

FIG. 11C illustrates a cross-section view of another embodiment of thepiston assembly 120 of the present disclosure, where the center post 126of the vent piston 134 has a recess 326 formed over a section adjacentthe inner end 224, such that the inner end 224 of the diaphragmcircumferentially engages the center post 126 other than the portion 226adjacent the recess 326, so as to maintain the permanently unobstructedcontinuous passageway 300 across the diaphragm 122 for the advantagesdescribed herein. Otherwise, the remainder of the structure andfunctionality of the pump assembly 100 remains as described herein, whenused in connection with this embodiment of the piston assembly 120.

FIG. 11D illustrates a cross-section view of another embodiment of thepiston assembly 120 of the present disclosure, where the vent piston 134include a projection 362 extending from the side wall 142 into contactwith the drive piston 150 such that the inner end engages the centerpost 126 other than the portion 226 that engages the projection 362, soas to maintain the permanently unobstructed continuous passageway 300across the diaphragm 122 for the advantages described herein. Otherwise,the remainder of the structure and functionality of the pump assembly100 remains as described herein, when used in connection with thisembodiment of the piston assembly 120.

FIG. 11E illustrates a cross-section view of another embodiment of thepiston assembly 120 of the present disclosure, where the vent piston 134include a projection 362 extending from the side wall 142 about thecircumference of the vent piston 134 into contact with the drive piston150 such that the inner edge 224 engages the projection 362, so as tomaintain the permanently unobstructed continuous passageway 300 acrossthe diaphragm 122 for the advantages described herein. Otherwise, theremainder of the structure and functionality of the pump assembly 100remains as described herein, when used in connection with thisembodiment of the piston assembly 120.

FIG. 11F illustrates a cross-section view of another embodiment of thepiston assembly 120 of the present disclosure, where the drive piston150 include an extension 364 that projects from the top wall 251 intocontact with the vent piston 134 such that the inner end 224 engages thecenter post 126 other than the portion 226 that engages the extension364, so as to maintain the permanently unobstructed continuouspassageway 300 across the diaphragm 122 for the advantages describedherein. Otherwise, the remainder of the structure and functionality ofthe pump assembly 100 remains as described herein, when used inconnection with this embodiment of the piston assembly 120.

FIG. 11G illustrates a cross-section view of another embodiment of thepiston assembly 120 of the present disclosure, where the drive piston150 include an extension 364 that projects from the top wall 251 aboutthe circumference of the drive piston 150 into contact with the ventpiston 134 such that the inner end 224 circumferentially engages theextension 364, so as to maintain the permanently unobstructed continuouspassageway 300 across the diaphragm 122 for the advantages describedherein. Otherwise, the remainder of the structure and functionality ofthe pump assembly 100 remains as described herein, when used inconnection with this embodiment of the piston assembly 120.

FIG. 11H illustrates a cross-section view of another embodiment of thepiston assembly 120 of the present disclosure, where an insert 366 isdisposed between and contiguous with the vent piston 134 and the drivepiston 150 about the circumference of the vent piston 134 and the drivepiston 150 such that the inner end engages the engages the insert 366,so as to maintain the permanently unobstructed continuous passageway 300across the diaphragm 122 for the advantages described herein. Otherwise,the remainder of the structure and functionality of the pump assembly100 remains as described herein, when used in connection with thisembodiment of the piston assembly 120.

FIG. 11I illustrates a cross-section view of another embodiment of thepiston assembly 120 of the present disclosure, where an insert 366 isdisposed between and contiguous with the vent piston 134 and the drivepiston 150 about a section of the circumference of the vent piston 134and the drive piston 150 such that the inner end engages the center post126 other than the portion 226 that engages the insert 366, so as tomaintain the permanently unobstructed continuous passageway 300 acrossthe diaphragm 122 for the advantages described herein. Otherwise, theremainder of the structure and functionality of the pump assembly 100remains as described herein, when used in connection with thisembodiment of the piston assembly 120.

FIG. 12 illustrates a cross-section view of another embodiment of pistonassembly 120 of the present disclosure including the vent piston 134having a hollow center post 126 where a second vent 380 is defined toextend through a wall of the center post 126 into the hollow 127. Thedrive piston 150 has a hollow center post 253 with a vent passage 254defined therethrough. Preferably, the hollow center posts 126, 254 ofthe vent piston 134 and the drive piston 150 are longitudinally alignedin registration and sealingly connected, such that a permanentlyunobstructed continuous passageway 300 across the diaphragm 122 that isdisposed at atmospheric pressure defined by the vent 136 in directcommunication with the channel 144 in direct communication with thesecond vent 380 in direct communication with the hollow 127 of thecenter post 126 of the vent piston 134 direct communication with thehollow 255 of the center post 253 of the drive piston 150 and theopening 239. Otherwise, the remainder of the structure and functionalityof the pump assembly 100 remains as described herein, when used inconnection with this embodiment of the piston assembly 120.

FIGS. 13A and 13B illustrate cross-section views of embodiments of adynamic vent 400 for the pump assembly 100 of the present disclosure.The vent piston 134 is configured to actuate a closure 402 between avent orientation and a vacuum orientation, wherein the vent orientationis defined when the vent piston 134 actuates the closure 402 to open thevent passage 404 so that the pressure chamber 146 is in directcommunication with atmospheric pressure 102 and the vacuum orientationis defined when the vent piston 134 is disengaged from the closure 402.One of skill in the art will recognize that the closure in thisembodiment is configured as a flap that covers and uncovers an openingbased on movement of the vent piston 134 and a projection or tetherassociated with the vent piston 134 and the closure 402, and that anyother suitable structure to facilitate the intended functionality iswithin the teachings of the present disclosure.

The above detailed description and the examples described therein havebeen presented for the purposes of illustration and description only andnot by limitation. It is therefore contemplated that the presentdisclosure cover any and all modifications, variations or equivalentsthat fall within the spirit and scope of the basic underlying principlesdisclosed above and claimed herein

1. A breast pump assembly comprising: a housing assembly including apiston housing and a drive housing having an opening in directcommunication with atmospheric pressure; a piston assembly including avent piston and a drive piston, the vent piston having a top wall and achannel defined by the top wall, a side wall and a center post where avent is defined to extend through the side wall in communication withthe channel; a rolling diaphragm including an outer end, an outer margindisposed adjacent the outer end, where both of the outer end and outermargin are sealingly captured between the piston housing and the drivehousing, an inner end, and an inner margin disposed adjacent the innerend, where the inner margin is sealingly captured between the ventpiston and the drive piston to cooperatively define a pressure chamberbetween the diaphragm, piston housing and vent piston; and a permanentlyunobstructed continuous passageway across the diaphragm that is disposedat atmospheric pressure defined by the vent in direct communication withthe channel, wherein the diaphragm is movable between a vacuumorientation and a vent orientation in response to cyclic movement of thepiston assembly, such that the vacuum orientation is defined when anouter opening of the vent is sealed by the diaphragm, and the ventorientation is defined when the outer opening of the vent is uncoveredby the diaphragm so that the pressure chamber is in direct communicationwith atmospheric pressure via the permanently unobstructed continuouspassageway across the diaphragm, and wherein the diaphragm is disposedin the vent orientation between 15% and 60% of each cycle of the pistonassembly.
 2. The breast pump assembly of claim 1, wherein the channel indirect communication with a portion of the inner end that is spaced fromthe center post.
 3. The breast pump assembly of claim 2, wherein theportion is defined by the inner end having a crenelated contour.
 4. Thebreast pump assembly of claim 2, wherein a plurality of ribs extend fromthe center post to engage the inner end.
 5. The breast pump assembly ofclaim 1, wherein the center post has a recess formed over a sectionadjacent the inner end.
 6. The breast pump assembly of claim 2, whereinthe vent piston includes a projection extending from the side wall intocontact with the drive piston such that the portion engages theprojection.
 7. The breast pump assembly of claim 2, wherein the ventpiston includes a projection extending from the side wall into contactwith the drive piston such that the inner edge engages the projection.8. The breast pump assembly of claim 2, wherein the drive pistonincludes an extension that projects from the top wall into contact withthe vent piston such that the portion engages the extension.
 9. Thebreast pump assembly of claim 2, wherein the drive piston includes anextension that projects from the top wall into contact with the ventpiston such that the inner edge engages the extension.
 10. The breastpump assembly of claim 2, wherein an insert is disposed between thedrive piston and the vent piston such that the portion engages theinsert.
 11. The breast pump assembly of claim 2, wherein the an insertis disposed between the drive piston and the vent piston such that theinner edge engages the insert.
 12. The breast pump assembly of claim 1,wherein the drive piston having a top wall with a vent passage definedtherethrough.
 13. The breast pump assembly of claim 12, wherein the ventpassage is in direct communication with the inner end portion and theopening.
 14. The breast pump assembly of claim 1, wherein the centerpost is a hollow center post and a second vent is defined to extendthrough a wall of the center post into the hollow.
 15. The breast pumpassembly of claim 14, wherein the drive piston has a hollow center postwith a vent passage defined therethrough, where the hollow center postsof the vent piston and the drive piston are longitudinally aligned inregistration and sealingly connected.
 16. The breast pump assembly ofclaim 15, wherein the inner end that circumferentially engages thecenter post.
 17. The breast pump assembly of claim 16, wherein thechannel is in direct communication with the second vent, the second ventin direct communication with the hollow of the center post of the ventpiston, the hollow of the center post of the vent piston in directcommunication with the hollow of the center post of the drive piston,and the vent passage in direct communication with the hollow of thecenter post of the drive piston and the opening.
 18. A breast pumpassembly comprising: a housing assembly including a piston housing and adrive housing, the piston housing having a vent passage in directcommunication with atmospheric pressure and a closure movably connectedto the piston housing that is configured to selectively seal the ventpassage; a piston assembly including a vent piston and a drive piston,the vent piston configured to actuate the closure between a ventorientation and a vacuum orientation; a rolling diaphragm including anouter end, an outer margin disposed adjacent the outer end, where bothof the outer end and outer margin are sealingly captured between thepiston housing and the drive housing, an inner end, and an inner margindisposed adjacent the inner end, where the inner margin is sealinglycaptured between the vent piston and the drive piston to cooperativelydefine a pressure chamber between the diaphragm, piston housing and ventpiston, wherein the vent orientation is defined when the vent pistonactuates the closure to open the vent passage so that the pressurechamber is in direct communication with atmospheric pressure and thevacuum orientation is defined when the vent piston is disengaged fromthe closure, and wherein the diaphragm is disposed in the ventorientation between 15% and 60% of each cycle of the piston assembly.19. A breast pump assembly comprising: a housing assembly including apiston housing and a drive housing; a piston assembly disposed withinthe housing assembly, the piston assembly including a vent piston and adrive piston; a rolling diaphragm including an outer end, an outermargin disposed adjacent the outer end, where both of the outer end andouter margin are sealingly captured between the piston housing and thedrive housing, an inner end, and an inner margin disposed adjacent theinner end, where the inner margin is sealingly captured between the ventpiston and the drive piston to cooperatively define a pressure chamberbetween the diaphragm, piston housing and vent piston; and a ventpassage in communication with the pressure chamber and atmosphericpressure, wherein the vent passage is selectively sealed to define avacuum orientation and a vent orientation.